A power converter has been known which includes a converter circuit for converting AC power of an AC power source into DC power, and an inverter circuit for converting an output of the converter circuit into AC power of a predetermined frequency. In such a power converter, a capacitor is generally provided on an output side of the converter circuit.
As such a power converter, for example, Patent Document 1 is known. In Patent Document 1, inverter control including control of a harmonics of the power source is performed on the basis of the detected power source current. Examples of a method of detecting a power source current include: a method using a current detection sensor called a current transformer (CT) (Patent Document 1); and a method using a current detection circuit including a shunt resistance and an operational amplifier instead of a current detection sensor (Patent Document 2).
However, when a current detection sensor is used, it is necessary to provide a space for arrangement of the sensor, resulting in an increase in cost of the sensor.
In the case of using a current detection circuit, since the number of components of the circuit is larger than that of a voltage divider circuit which is used for detecting a DC voltage and has a simple configuration, resulting in an increase in cost. Furthermore, it is necessary to provide an arrangement space for the components of the current detection circuit on a printed wiring board.
On the other hand, as disclosed in Patent Document 3, there is a method of estimating a power source current without detecting the power source current.